Since the inception of the monopolar and bipolar electro-surgical unit in surgery as tools to the surgeon for cutting and coagulating tissues, numerous cases of inadvertent and unwanted electrical shocks and burns to the patient and physician have been reported (Peters, 1991; Wicker, 1990; Association of Operating Room Nurses, 1990). In a great number of these reports, the cause of the reported injury was specified as resulting from the breakdown of the electro-surgical instrument's insulation.
The insulation material typically utilized has been teflon, PVC, or heat shrink plastic materials. While these materials do have exceptionally well-documented electrical insulative characteristics, they are severely lacking as ideal insulators for surgical instruments. The primary reasons for this are that they have very little abrasion resistance (i.e. coating wears off easily). In addition, they can be scratched easily, leaving areas with bare metal exposed. They degrade rapidly with various sterilization methods, causing insulative properties to deteriorate; and additionally, they can retain moisture between bare metal and insulation contributing to problems of corrosion and to problems with sterilization.
Also they have low resistance to heat. The insulation degrades with heat generated by wattage flowing through the instrument during prolonged use, and finally the currently utilized instrument insulations must be replaced regularly which results in excessive costs to health care providers.
It is the applicant's belief after analysis of the technology that the ideal insulator for electro-surgical instruments would have at least the following characteristics. It should have excellent dielectric (insulative) properties in the 500 KHZ to 1 MHZ frequency range which is typical of electrosurgery unit generators. In addition, it should have exceptional wear and abrasion characteristics, and should be impervious to scratching, nicking or cutting. It should be chemically inert and sterilizable, non-toxic, non-irritating, and non-cytotoxic, and be acceptable for use in the human body. It should adhere rigidly to the base metal of the instrument to prevent corrosion and sterility problems. It should be cost effective and it should be unaffected by various sterilization techniques and finally it should be readily applicable to a variety of shapes and sizes of surgical instruments.